The previous effort toward the total synthesis of the gastrointestinal hormone cholecystokinin-pancreozymin (CCK), a 33-peptide, Lys-Ala-Pro-Ser-Gly-Arg-Val-Ser-Met-Ile-Lys-Asn-Leu-Gln-Ser-Leu-Asp-Pro-Ser-His- Arg-Ile-Ser-Asp-Arg-Asp-TyrSO3H-Met-Gly-Trp-Met-Asp-Phe-HN2 was continued Attempts are made to eliminate the side reactions which interfere with the unequivocal synthesis of CCK. These experiments are expected to improve the methodology of peptide synthesis.